Crankpin turning tool



May 16, 1950 l. D. ZITZERMAN CRANKPIN TURNING TOOL Filed April 29, 1946 INVENTOR ATTOR N EYS.

Patented May 16, 1950 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to turning tools, particularly for truing the `pins of a crankshaft without removal thereof from its operating position, and has for its principal object to provide a tool of this character which is extremely accurate in operation and smoothly faces the cylindrical surfaces of a crankpin as well as the llets and cheeks of the crank.

This invention is an improvement over my Patent No. 2,219,245 granted October 22, 1940.

Other objects of the invention are to provide a tool of this character adapted for turning crankpins of different diameter with extreme accuracy; to provide a bearing for the adjusting screws of the device; to provide the tool with a secure cutter mounting to avoid its becoming out of balance and thus avoid chatter during cutting operation of the tool; to provide a plunger assembly for the device for resiliently contacting the crankpin worked upon; to hold the device relative to said pin; to provide seating plates for contacting the cheeks of the crank; and to provide removable mountings for said plates.

In accomplishing these and other objects of the invention, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. l is a perspective view of the lower portion of a crankcase of an internal combustion engine showing an oil pan removed and my improved turning tool applied to one of the crankpins.

Fig. 2 is a sectional View through the tool.

Fig. 3 is a section taken on a line 3-3, Fig. 2.

Fig. 4 is a detailed perspective view of the parts of the turning tool shown in disassembled spaced relation to better illustrate the construction thereof.

Referring more in detail to the drawings:

I designates a turning tool constructed in accordance with the present invention and which includes a substantially ring-like body 2 composed of mating arcuate sections 3 and 4, said sections being of less width than the minimum width of a pin 5 on which the tool is to be used so that it is freely rotatable about the axis of the pin between the cheeks 6 and 'I of a crank 8. The inner arcuate faces 9 and I0 of the respective sections are of suitable diameter to accommodate the largest size pin for which the tool is to be used, and the outer arcuate faces I I and I2 are of suilicent diameter to give the required rigidity and metal necessary in mounting the connecting guide pins I3' and I4 by which the sections are interconnected. The adjacent end faces I5 and I6 of the respective sections extend on parallel planes so that the sections may be brought closely together when applied to a crankpin of minimum diameter.

Extending inwardly from the faces I6 of the respective sections are cylindrical bores I 1 adapted to receive the guide pins I3 and I4 which are seated therein against the bottom of the bores and held securely therein by pins I S extending transversely through the body of the respective Sections 3 and 4. The guide pins I3 and I4 are of sufficient length to project from the faces I6 to form guide portions slidably receivable in registering bores I9 extending inwardly from the faces I5 at the opposite sides of the respective sections. The projection of the pin I4 is slightly greater than that of the pin I3 so that the pin I4 is caused to enter its receiving bore ahead of the pin I3 to facilitate assembly of the device.

The pins I3 and I4 are provided with threaded axial bores 2U to be engaged by the threaded Shanks 2I of adjusting screws 22. The adjusting screws 22 are provided with collars 23 and heads 24 spaced from the collars providing annular grooves 25 therebetween. The heads 24 are exposed within one side of the counterbore and are provided with micrometer scales 26, the divisions of which are adapted to register with zero scales 21 as best shown in Fig. 4. The heads of the adjusting screws are provided with hexagonal sockets 28 for the insertion of a suitable tool whereby the screws are rotated to thread the Shanks thereof to and from the threaded bores 23 of the guide pins, thereby connecting and disconnecting the sections and effecting adjustment in spacing thereof to accommodate crankpins of different diameter.

The sections 3 and 4 are provided with slots 29 extending transversely of and intersecting the bores I9 in the respective sections. The slots are adapted to receive a keeper 30 having a substantially cylindrical head 3l and shank portion 32. The cylindrical head is provided with a slot 33 adapted to engage the annular groove 25 provided between the collar 23 and head 24 of the adjusting screws 22. The slots 29 extend beyond the bores I9 in the sections and the keeper, providing a bearing for the adjusting screws, the shank 32 of the keeper providing a handle for insertion and removal of the keeper as will later be shown.

Formed in the arcuate faces II and I2 of the sections are sockets 34 whereby a suitable handle or bar 35 may be inserted to effect rotation of the tool as later described.

The section is adapted to constitute a support for a cutter 36 and a plunger assembly 31.

The section 4 supports spaced seating plates 38 and 39 for seating the tool against the crankpin 5. The cutter 36 is best illustrated in Fig. 4 and constitutes a flat blade having side faces te, edge faces 4| and end faces 42. The junctures of the faces 40 and 4| form cutting edges 43 adapted to remove material from the circumference of the pin and the juncture of the faces 49 with the end faces 42 forms cutting edges 4d to remove material from the cheeks 6 and 'l of the crank. The corners of the cutter are rounded as at 45 to form the fillets 49 of the crank so that the crankpin, cheek faces and llets are simultaneously surfaced upon actuation of the tool as later described.

The cutter 36 is seated in a transverse groove 41 extending inwardly of the arcuate face l0 and of the section 3 which forms a shoulder 4B against which the cutter is rigidly secured by a wedge member 49 having one side bearing against the cutter and its opposite side against. the op.- posite side or shoulder 5S of the groove .as shown in Fig. 2. The wedge plate is drawn into wedging relation with the cutter by fillister screws 5| having their heads 52 rotatably mounted in counterbores of the wedge and their Shanks 53 extending through registering openings 54 into threaded sockets 55. at the bottom of the groove 41. The shoulder 4.8 is so positioned in the section 3 that when one side face of the cutter is wedged thereagainst, the opposite side face will lie in a plane extending through the axis of a crankpin toV which the tool is applied. The cutting edge 43 thereof contacts the cylindrical surface of the pin at the diametrical axis thereof andthe adjacent edge face 4| cooperates with the cylindrical surface to provide suicient clearance at the retractive side of the cutter when the tool is. rotated about the axis of the crankpin in the direction of the arrow as shown in Fig. 2.

In order that the cutting edge of the cutter when positioned as shown in Fig. 2 will at all times remain in a diametrical plane with respect to the crankpin regardless of the diameter thereof, I have found that the cutter will operate best positioned at substantially twenty-seven degrees. from the medium line of the arcuateface 9 of the section 3. It is also essential that the plates 38 and 39 have plane surfaces for tangentially contacting the cylindrical surface of the L;

crankpin, that the seating plate 39. be located directl-y opposite the cutter, and that the plane surfaces be located at right angles to each other also as shown in Fig. 2. The seating plates 38 and. 39preferably have dovetail edges 5B and 51 to engage in dovetail grooves 58 provided in the arcuate face H) of the section 4.

The pin contacting faces 59 of the seating plates are preferably fiat so that they extend tangentially with respect to the cylindrical surface of the crankpin. The plates 38 and 39 are of sufficient thickness to extend slightly above the cylindrical surface I9 of the section d and of a length to extend beyond the side faces of said section as best illustrated at 6|] (Fig. 4)

In order to retain the seating plates 3.5 and 39 firmly in tangential contact with the crankpin to be resurfaced, the section 3 is provided with the plunger assembly 3l which is located therein diametrically opposite to the `midpoint between the seating plates 38 and 39. The plunger assembly includes a bar Gislidable in a slot 62 extending transversely of the arcuate face 9. of the section 3. The bar 9| has a shank 63 slidable in a bore 64 registering with the slot 62. The bore S4 extends from the slot S2 to the outer edge of the section 3 and the outer portion thereof is internally screw threaded as indicated at 6'! adapted to receive a screw |58. The Allen screw is provided with a hexagonal socket 69 for the insertion of a suitable tool for rotation of the screw as later described. The shank 63 is provided on its outer end with a collar l! providing an annular groove 'Il adapted to receive the end of a coil spring 'l2 to retain the bar 9| on the spring. The opposite end of the spring is adapted to engage against the end of the screw 68 as indicated at T3 (Fig. 2). It will thus be obvious that by adjusting the screw in the bore 50., tension may be exerted on the bar 6| to engage against the crankpin 5. The distance the bar 6| may be extended inwardly is limited by the collar 66 abutting against the internal shoulder 65. The plunger assembly is removable outwardly through the bore 64.

Irl-order to cooperate with the cutter in centering the tool between the cheeks 6 and'l of the crank. 8.. the plates 38 and 39 extend slightly beyond the sides of the section 4 as indicated at 60 i (Fig. 4) and as. shown in Fig. 3 so that the ends of the plates engage against the respective cheeks, thereby retaining the outer side faces of the tool parallel with the cheeks 6 and 1. The section 4 is provided with threaded bores 14 adapted to receive the threaded shanks 'l5 of set screws 16 having tapered heads Tl for retaining the plates 3.13 and 39 in their respective grooves 58. The bores 'H are countersunk as indicated at 'I8 (Fig. 4), so that the tapered heads of the screws will not interfere with the crankpin during operation of the device.

In using a tool constructed as described for resurfacing a crankpin 5, it is only necessary to remove the oil pan of the engine. The connecting rod bearing is then removed from the crankpin to permit application of the turning tool. It is not necessary to remove the connecting rod or piston. When the piston is moved to the top of the cylinder, the connecting rod is carried therewith which leaves suicient room therebelow to operate the tool. The keeper 3U is removed from engagement with the adjusting screws 22 0f the turning tool. The screws are then removed from the guide pins so that the sections of the tool may be separated to permit application thereof to the crankpin. Before applying the tool to the crankpin a cutter St of proper length is inserted in position within the section 3 and securely tightened by the, wedge element 49. The sections 3 and l are then placed about the pin to be surfaced so that the guide pin |4 enters the bore I9 of the section 4 prior to entrance of the guide pin I3 in the bore I9 of the section 3. This is an important feature since it facilitates mounting ol' the tool on the crankpin. The adjusting screws are then reapplied to secure the sections together and draw them together so that the seating plates 39 and 33 contact one side of the bearing pin and the plunger 6| the opposite side, thereby centering the tool for rotation about the axis of the pin. The adjusting screws are drawn up until the cutting edge of the cutter engages the cylindrical periphery of the pin so that when a bar is inserted in the sockets 34 to rotate the tool in the direction of the arrow (Fig. 2), surface is removed from the crankpin to form a true cylinder. Since the cutting edge of the cutter is at all times kept in substantially the diametrical axis of the pin and the plates 38 and 39 seated against the opposite sides thereof by the plunger, the tool will not become crooked on the pin and will thus avoid chatter when rotated. The cut is, therefore, smoothly uniform and true cylindrically with respect to the axis of the pin. The ends of the cutter and the rounded corners thereof also form cutting edges which true up the cheeks 6 and 1 as well as the fillets at the ends of the pin. The amount of each cut may be noted by the micrometer scales on the heads of the adjusting screws so that the Idesired reduction may be effected in the size of the pin.

When the tool is to be applied to a smaller shaft as shown by dotted lines in Fig. 2, the plates 38 and 39 will maintain their tangential contact with the smaller shaft and the drawing together of the sections will move the cutting edge of the cutter downwardly toward the smaller shaft in a plane parallel with the vertical axis :as respectively indicated by the plane lines 19 and 80.

From the foregoing it is obvious that I have provided a turning tool adapted for accurate work and which will simultaneously finish all of the varying surfaces of a crankpin with a single application of the tool. It is also obvious that the tool is readily applied to a crankpin without removing the crankshaft from its operating position since the tool may be readily rotated about the shaft by alternating engagement of the turning bar with respect to the sockets 34 in the respective sections.

It will further be obvious that I have provided an improved bearing for the adjusting screws by providing the keeper for the same and also providing a plunger assembly which will maintain the plunger bar resiliently against the crankpin Without adjustment after its initial setting.

What I claim and desire to secure by Letters Patent is:

In a, crankpin turning tool of the character described, a, pair of mating arcuate sections, guide pins in opposite ends of the respective sections and slidably engageable in aligning through bores in the opposite facing ends of the sections, said guide pins having axial threaded bores opening from the ends thereof, adjusting screws having heads rotatable and slidable in the through bores and Shanks threadedly engaging the threaded bores in the guide pins to selectively move said heads toward and away from the guide pins in response to turning of the adjusting screws, said adjusting screws each having an annular groove intermediate the ends of the `head thereof, transverse slots in the arcuate sections extending from the peripheries thereof and intersecting said through bores and forming opposite faces substantially aligning with the side edges of the grooves in the heads of the adjusting screws in the respective bores. a U-shaped` member removably mounted in each of the slots with opposite faces of said member engaging the respective faces of the slots and side edges of the grooves for preventing relative longitudinal movement of the adjusting screw heads and the respective sections whereby turning of said screws effects relative movement of the sections, removal of said U-shaped members from the slots freeing the sections for separation thereof, a cutter supported by one of the sections, seating plates supported in the other section and cooperating with the cutter to engage a cylindrical surface of a crankpin upon manipulation of the adjusting screws, and graduations on the heads of the adjusting screws registrable with markings on the sections for spacing the sections to position the cutter with respect to said seating plates.

ISAAC D. ZITZERMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,403,813 Pinto Jan. 17, 1922 1,466,881 Johnson Sept. 4, 1923 1,467,501 Roney Sept. l1, 1923 1,841,337 Roessler Jan. 12, 1932 2,219,245 Zitzerman Oct. 22, 1940 

